Safety Shutdown Messages - York YK Style H Operation Manual

FORM 160.76-O2
issue date: 6/15/2015
VSD – Harmonic Filter-Precharge-Low DC
Bus Voltage
(575V/60Hz applications)
If the DC Link Voltage does not reach at least 60VDC
(within 100 millisconds) or at least 630VDC (within 5
seconds) after the filter precharge command has been
received, this shutdown is performed.
Harmonic Filter – Low DC Bus Voltage
The Harmonic Filter generates its own Filter DC link
Voltage by switching its IGBT's. This DC level is ac-
tually higher than the level that one could obtain by
simply rectifying the input line voltage. Thus, the
Harmonic Filter actually performs a voltage BOOST
function. This is necessary in order to permit current to
flow into the power line from the filter when the input
line is at its peak level. This shutdown occurs when the
Filter's DC Link Voltage decreases to a level less than
60VDC below the Filter DC Link Voltage setpoint.
This Setpoint is determined by the Filter Logic Board
via the sensing of the three phase input line-to-line
voltage. This setpoint is set to the peak of the sensed
input line-to-line voltage plus 32 volts, not to exceed
760 volts and it varies with the input line-to-line volt-
age. If this shutdown occurs occasionally, the likely
cause is a severe sag in the input line voltage.
Harmonic Filter – DC Bus Voltage Imbalance
The Filter DC link is filtered by large, electrolytic ca-
pacitors, rated for 450VDC. These capacitors are wired
in series to achieve a 900VDC capability for the DC
link. It is important the voltage is shared equally from
the junction of the center or series capacitor connec-
tion, to the negative bus and to the positive bus. This
center point should be approximately ½ of the total DC
Link Voltage.
VSD – Harmonic Filter-DC Bus Voltage
Imbalance
(575V/60Hz applications)
If the Half DC Link Voltage does not remain within
plus or minus 63VDC of the DC Link Voltage divided
by 2, this shutdown is performed.
Harmonic Filter – Input Current Overload
The three phases of RMS Filter current are monitored
and if any one of the three phases continuously exceeds
a given threshold for 7 seconds, a chiller shutdown is
performed and this message is displayed. The maxi-
JOHNSON CONTROLS
SECTION 3 - DISPLAY MESSAGES
mum permissible continuous RMS current ratings for
the Harmonic Filter are:
• 351/292 HP equals 128 Amps
• 503/419 HP equals 176 Amps
• 790/658 HP equals 277 Amps
• 1048/917 HP equals 385 Amps
Harmonic Filter – Logic Board Power Supply
The low voltage power supplies on the Filter Logic
Board have decreased below their permissible operat-
ing range. The Filter Logic Board receives its power
from the VSD Logic Board via the ribbon cable, con-
necting the two boards.
Harmonic Filter – Run Signal
When a digital run command is received at the Filter
Logic Board from the VSD Logic Board via the 16 po-
sition ribbon cable, a 1/10 second timer is started. If a
redundant run command does not occur on the serial
data link from the VSD Logic Board before the timer
expires, a shutdown is performed and this message is
generated.
Harmonic Filter – DC Current Transformer 1
During initialization, with no current flowing through
the DC Current Transformers (DCCT's), the DCCT
output voltages are measured and compared with a
preset limit via the Filter Logic Board. If the measured
values exceed the preset limits, the DCCT's are pre-
sumed to be defective and this shutdown is generated.
Harmonic Filter – DC Current Transformer 2
See Harmonic Filter – DC Current Transformer 1 mes-
sage above.

SAFETY SHUTDOWN MESSAGES

Evaporator – Low Pressure
The Evaporator Pressure, as sensed by the Evapora-
tor transducer, has decreased to the safety shutdown
threshold. For water cooling applications, the safety
shutdown threshold is a fixed value for the respective
refrigerant. For Brine cooling applications, the safety
shutdown threshold varies according to the concentra-
tion of the Brine solution. The Brine shutdown thresh-
old is programmed at the YORK Factory. It should not
be changed by anyone other than a qualified Service
Technician following instructions in OptiView Control
3
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